Large systematic deviations in a bimanual parallelity task: further analysis of contributing factors

Influence of gaze elevation on estimating the possibility of passing under high obstacles during body tilt

“…The second hypothesis supports the existence of intermediate states, in which egocentric, allocentric and geocentric cues would merge into a hybrid reference frame (Flanders and Soechting 1995;Kappers 2003Kappers , 2004Paillard 1991;Soechting and Flanders 1992). For instance, Kappers (2004) found a combined contribution of allocentric and egocentric cues in the haptic judgment of parallelism.…”

“…The second case refers to the existence of an intermediate reference frame in which the contribution of each egocentric, allocentric or geocentric cues is kept constant and stable throughout the task (Bringoux et al 2004(Bringoux et al , 2007(Bringoux et al , 2008Kappers 2003Kappers , 2004Neggers et al 2005). For instance, Bringoux et al (2008), showed that egocentric references could influence the perceived location of objects relative to some geocentric references, each with a constant weight, whatever the tilt magnitude.…”

Haptic perception: A tutorial

“…Figure 10C shows the adjustments made by one subject with her right hand to perceptually match the parallelism of the rods presented in Figure 10B. Figure 10D shows the wide range (8º-91º) of individual subject errors observed in one study (Kappers, 2003), depending on the position of the adjustable bar relative to the reference bar. A model proposed to account for these results suggested that subjects used two competing frames of reference, one centered on the body (most probably the hand) and the other anchored to external space.…”

The perception and representation of orientations: A study in the haptic modality

“…In all these studies, the systematic errors were smallest at the vertical, horizontal and diagonal orientations and biased toward the nearest diagonal at the oblique orientations that lay between the cardinal and diagonal orientations (e.g., near 30°or 60°). In the haptic modality, some evidence for the existence of a similar orientation-specific bias can be found in orientation matching studies even if this bias is masked by the larger systematic errors induced by the transfer of the reference orientation between two positions in space in the parallelity task (Kappers, 2003(Kappers, , 2004Postma et al, 2008;Zuidhoek, Kappers, & Postma, 2005). While these studies provide some hints that a bias toward the diagonals might be present within an egocentric frame of reference (see in particular Volcic, Kappers, & Koenderink, 2007), the effect of orientation on the pattern of systematic errors has yet to be investigated with a large set of orientations in a haptic orientation perception task that does not involve a shift of position.…”

“…Spatial information is always specified with respect to some frame of reference (Howard, 1982) and many studies on the perception of orientations have focused on identifying it (Kappers, 1999(Kappers, , 2003(Kappers, , 2004Luyat et al, 2001;Volcic, van Rheede, Postma, & Kappers, 2008;Volcic et al, 2007). However, the concept of reference frame per se does not explain why or how directional anisotropies occur within the possibly rotated subjective frame of reference since it fails to explain what might cause orientation-specific variations in the accuracy and precision of the responses such as the directional bias toward the diagonal.…”